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CRT Filter

26 May 2004

Johnson Matthey (JM) has received US EPA verification for its CCRT™ diesel particulate filter system. Once verified, the system is eligible for use in the EPA’s Voluntary Diesel Retrofit Program (VDRP) and other diesel retrofit programs in the USA.

This verification is an extension of the CRT® filter verification that was completed under the NESCAUM Third Party Verification System. Both the CRT and CCRT filters (as well as filters from other manufacturers verified through NESCAUM) generate SIP emission credits of 60% for PM, CO, and HC.

JM’s CRT (Continuously Regenerating Technology) filter system includes an oxidation catalyst positioned upstream of an uncatalyzed particulate filter. The filter is regenerated using nitrogen dioxide generated in the catalyst. The CCRT configuration—which stands for Catalyzed CRT—includes an upstream catalyst and a catalyzed particulate filter. Thus, it combines the regeneration mechanisms found in the CRT filter and in catalyzed filters.

The CCRT filter has been verified for use with fuels of sulfur content below 30 ppm. For regeneration, an exhaust temperature of above 210°C is required for 40% of the duty cycle (the temperature requirement was 275°C for 40-50% of the duty cycle in the NESCAUM verification for the CRT filter).

Johnson Matthey said the CCRT has been successfully operating in applications that are too cold for the CRT filter, such as school buses in California and Massachusetts.

This verification will be posted on the EPA website shortly.

EPA verification letter

Source: Johnson Matthey